1. Field of the Invention
The present invention relates to an incremental encoding slide operating device which detects a position of an operating knob by sensing markings such as magnetic poles provided on a linear scale with a sensor portion which travels along the linear scale.
2. Description of the Related Art
As disclosed in Japanese Patent Laid-Open Publication No. 2006-49302 and Japanese Patent Laid-Open Publication No. 2003-21541, for example, such a slide operating device is employed as a fader device for setting a parameter, the fader device being provided on a mixing console.
Japanese Patent Laid-Open Publication No. 2006-49302 discloses a slide operating device having a magnetic linear scale. In the disclosed slide operating device, a magnetic sensor composed of an MR element is mounted to a moving block, while a magnetic pattern in which a north pole and a south pole are alternately arranged is applied as markings to one of paired parallel guides which hold the moving block. In this disclosed art, when the moving block travels by a manual operation of a slide operator or by actuation of a motor, the magnetic sensor outputs pulse signals in accordance with the magnetic poles of the linear scale to allow the detection of the amount (length) of travel of the moving block in accordance with the number of the pulse signals.
Japanese Patent Laid-Open Publication No. 2003-21541 discloses a non-contact digital fader. In this non-contact digital fader, when a moving member travels by a manual operation of a knob or by actuation of a motor, an optical sensor reads a pattern of light and dark recorded on a linear scale to count a relative position on the linear scale to calculate the position of the optical sensor. In this conventional art, the non-contact digital fader also has a sensor for sensing a reference position.